Tuesday, 15 March 2011

Radiation Dosage Chart



From http://stephenslighthouse.com/
at 3/15/2011 10:59:00 pm
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12 comments:

Anonymous said...

Where did this chart come from.

Applying a little common sense a chest X-ray wouldn't be very clear if the amount of energy needed to make one was lower than the background radiation now would it?

Where did you dig up this peace of propaganda?

Thursday, March 17, 2011 2:05:00 am
Anonymous said...

After looking into the origin of this chart I'm disappointed in you.

How about some real facts for a change.

Thursday, March 17, 2011 2:09:00 am
Zoe Brain said...

The background is the dose received over a year. The X-ray doesn't take quite that long, though if you left an undeveloped X-ray plate out of shielding for a year, it would get fogged.

I always give my sources, so you can check for yourself. He got his data from various health agencies, nuclear safety organisations, at least one from a professional radiologist organisation, and I've checked vs a variety of primary sources.

Thursday, March 17, 2011 2:34:00 am
Grace said...

Well, an x-ray takes, very roughly, 1 second. The second line on that chart says exposure "in one year". Applying a little common sense, let's use math to compare apples and apples.

There are roughly 31,557,600 seconds in a year. If a one-second chest x-ray exposes a person to 0.1 mSv, then a one-year chest x-ray would expose a person to 3,155,760 mSv, or 3155 Sv.

Looked at another way, if one year of background radiation exposes a person to 3 mSv, then one second of background radiation exposes a person to about 9.5x10^-8 mSv.

So according to the chart, a chest x-ray is about 100,000 times more radiation, PER UNIT TIME, than background radiation.

Is there a radiation exposure chart you prefer, Nyf? If so, where is it and why do you prefer it?

Grace

Thursday, March 17, 2011 2:37:00 am
Grace said...

Also, I recall vaguely from long-ago reading that rate matters, in matters of radiation exposure. Over many years, people can survive exposures which might kill them if they happened all at once. However, if memory serves, total lifetime exposure is supposed to be a good first approximation for a person's risk.

Grace

P.S. Darn, Zoe. You beat me to it by three minutes. :)

Thursday, March 17, 2011 2:45:00 am
Anonymous said...

Zoe you are mixing apples and oranges than if you are using one time interval for one type of exposure and another for another type of exposure.
This is dishonest at the very least.

This graph has no real meaning, it's just like AL Gore's hockey stick graph, no numbers, no time frame, the only difference is you are presenting an oversimplistic view of the dangers involved in ionizing radiation and in doing so providing misinformation.

I would advise you to stick to model rockets, that seems to be your forte.

Thursday, March 17, 2011 2:57:00 am
Zoe Brain said...

The amounts are amounts in one exposure, dimemsionless other than the Sieverts.

Where there is a time element, that's indicated on the left.

e.g. "Living on the Colorado plateau for one year" means you get a total dose of 4.5 mSv. That is, 4,500 microSv over that time.

"Getting a full body CT scan", whether it takes 5 mins or 15 mins, gives you a total dose of 10mSv, that is, 10,000 microSv.

"lowest dose for any statistical risk of cancer" should say "lowest dose over the course of one year for any statistical risk of cancer".

That's 50 mSV, 50,000 microSv, or 5 Rem. It's the standard "safe" dose.

If you stood on top of the #3 reactor, and waited an hour, you'd get a dose of 400,000 microSV, or 400 mSV, or 0.4 Sv, or 40 Rem.

Not enough for symptoms of Radiation Sickness, BUT an increase of perhaps 30% in cancer rate, a suppressed immune system for a while, and a blood count would detect you'd been exposed to radiation.

Even with PF 10 suits, a worker could only put in a few minutes before exceeding their yearly dose - remember, they've already had 3.5 Rads from normal background. So they're only allowed another 1.5 Rem on top of that. Work there for 20 mins in a PF (protection factor 10) suit, and you'd be over.

Thursday, March 17, 2011 3:21:00 am
Zimbel said...

@NotYourFriend-
This is a fairly typical way of describing radiation risk. - for example, we usually measure human lifespans in terms of years, but X-rays in number of X-ray exposures. However, if you'd prefer to normalize the data to a standard length of time, please feel free to do so. You may also want to standardize on a single unit; the mSv -> Sv transition makes it marginally harder to compare the top of the chart to the bottom.

All that said, I find this chart useful as it is.

Thursday, March 17, 2011 3:32:00 am
Anonymous said...

You had better revise your figures Zoe. the number three plant has part of the core exposed.

I suggest you look for a different news outlet.

The situation is a whole lot worse than you might think.

Thursday, March 17, 2011 5:30:00 am
Rob said...

Zoe,

I think your information is spot on, and your answers to "notyourfriend" very detailed, illuminating and patient.
If I were you, I'd ignore "notyourfriend" ... he/she sounds like an ignoramus of the first order.

Thursday, March 17, 2011 9:27:00 am
Di said...

Notyourfriend, I can only assume that the process of leaving a dissenting comment, is somehow a cathartic process for you. Your comments are not accurate. For the medical radiation exposure end of the spectrum, I recognise the figures in the table as being the widely accepted standards. No skullduggery to be had there, sadly for you, I guess. Although perhaps all you require is someone else saying something - anything - for you to rub your hands in glee, and post a rebuttal. I that case, carry on, if it makes you feel better. That will leave everyone else to continue the discussion, pausing politely when you speak, and then resuming the conversation.

Thursday, March 17, 2011 10:20:00 am
Anonymous said...

Well maybe some of you should be watching the news.
The latest news is the radiation outside of Unit 4 are 40 REMs per hour. That is not anywhere near a healthy dose.
Even Zoe knows that.

j

Thursday, March 17, 2011 11:34:00 am

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